


The Chamber of Secrets

by FantasticNumberNine



Series: John Watson and the Chamber of Secrets [10]
Category: Harry Potter - J. K. Rowling, Sherlock (TV)
Genre: AU, Crossover, Fighting Monsters, Gen, Potterlock, Solving the mystery, alls well that ends well, his skeleton will lie in the chamber forever, john Watson will save your life, the Heir of Slytherin
Language: English
Status: Completed
Published: 2014-09-12
Updated: 2014-09-12
Packaged: 2018-02-17 03:37:49
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,061
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2295305
Author URL: https://archiveofourown.org/users/FantasticNumberNine/pseuds/FantasticNumberNine
Summary: <blockquote class="userstuff">
              <p>The pieces fall together, but it might just be too late for them to save Sherlock Holmes--the Heir of Slytherin has promised that his skeleton would lie in the Chamber forever.</p>
            </blockquote>





	The Chamber of Secrets

**Author's Note:**

> *disclaimer*
> 
> The final installment for Year 2!

John and Greg never found the time to question Moaning Myrtle.

" _Exams_!" Howled Seamus Finnigan. "Were still getting " _exams_?"

It had never occurred to John that he would still need to sit through exams with the castle in this state. He couldn't even remember learning anything that would be _useful_ in an exam. Greg looked like he'd been told to pack up and move into the Forbidden Forest beside him.

"Can you imagine me taking exams with this?" He held up his battered wand and it began whistling loudly of its own accord.

Several days before their first exam McGonagall announced that the mandrakes were ready to use at last, and everyone who had been petrified would be woken that very evening. 

"Are you imagining the look on Myc's face when he finds out we're still sitting exams? He'll be livid!" 

John raised an eyebrow, "I was actually imagining what it would sound like when he tells us who's been opening the Chamber of Secrets."

Greg stared at him, "Yeah, alright. Less fun though."

Sherlock appeared from thin air, sliding into the seat next Greg and wringing his hands nervously. 

"What's up, Sherlock?" Greg asked, pausing in the act if serving himself more porridge.

Sherlock didn't say anything, glancing instead up and down Gryffindor table with a familiar look of fear, though John couldn't remember where he knew it from.

"Spit it out, Sherlock," said Greg, watching him intently now.

John recognized the look now, as Sherlock rocked slowly in his seat. Dobby had been the same when he'd been thinking desperately of revealing forbidden information.

"I've got to tell you something," Sherlock mumbled, not looking at John or Greg.

"What is it?" Greg asked kindly.

Sherlock seemed incapable of finding the right words. John leaned in slowly, speaking quietly so that only Sherlock and Greg would hear him.

"Is it something about the Chamber of Secrets? Have you seen something?"

Sherlock took a deep breath, but at that moment, Percy Lestrade appeared, looking exhausted.

"If you've finished eating, I'll take that seat, Greg. I'm starving, only just came in off patrol duty."

Sherlock leapt off his chair, looking terrified before dashing away. Greg groaned and glared at his brother before standing, dragging John with him.

"Percy, you prat! He was just about to tell us something important!" Greg said angrily, and stormed out, leaving John to follow with a long sigh.

Despite knowing that they would get all the answers that evening from Mycroft--and likely with many remarks on the obviousness of it all--John still wanted to question Myrtle, and being a good friend, Greg joined him. They were caught by Professor McGonagall just as they were about to congratulate themselves on tricking Lockhart.

"We wanted to go see Mycroft, Professor--"

"--Only it's been ages since we've seen him--"

"--And we wanted to let him know the mandrakes were ready--"

"--And Sherlock asked if we'd go see him, he's too scared to go himself--"

"--So we told him we'd say hello for him, as we were going to try and see him--"

"--We miss him, Professor. He's our friend."

Professor McGonagall stared at them, and for a moment John thought they were about to be in a lot of trouble. Again. But when she spoke, it was in a strangely croaky voice.

"Of course, I realize this has been hardest on those of you who have been... Yes, I quite understand. Yes, Watson, Lestrade, you may visit Mr. Holmes. Tell Madam Pomfrey I have given my permission."

Now they were sitting next to Mycroft, neither of them sure what to say--Mycroft was petrified, he hadn't any idea his friends were sat beside him. 

Greg was saying something, but John's attention was on Mycroft's hand: a scrunched piece of paper was clenched there, against his chest. Making sure Madam Pomfrey wasn't nearby, John leaned forward to pry it free.

"What're you, oh! What is it?" Greg leaned in to look and choked back a laugh, "Did _Myc_ tear out a page from a book? A page from a _library_ book?"

John smiled, smoothing out the very old page--indeed torn from a library book--and they read it together.

"A basilisk! No wonder I could hear it, it's a great, monstrous snake!" John breathed.

"But it hasn't _killed_ anyone, how--"

"That's probably why it took Mycroft so long to figure it out, but think about it, Greg! It's got to look it's victim directly in the eyes to kill it!"

Greg frowned, still unsure what that had to do-- 

"Oh! The mirror?"

"The mirror--Mycroft knew the thing was around when he was in the library. He probably found that Ravenclaw girl on purpose, knowing she'd have a mirror to look around corners with! No one's been looking at it directly, so no one's died yet!"

"Creevey saw it through his camera... Knight... Through Nearly Headless Nick--who probably _did_ look at it directly, but he was already dead... Myc and the Ravenclaw saw it in the mirror..." Greg paused, thinking. "And Mrs. Norris? Why isn't she dead?"

John stared at the page, knowing he knew the answer, "The water! There was water everywhere, remember? The bathroom had been flooded!"

The boys were beaming, the adrenaline of case solving with the knowledge that Mycroft would be waking soon putting them in a better mood than their trek through the forest had left them in.

"There's one thing I still don't understand though," John said after a moment.

"Who's been opening the Chamber?"

"Alright, two things I still don't understand. How has no one noticed a giant snake roaming the castle?"

Greg shook his head, "Myc figured that out too, shouted it at us before he tore off for the library. It's been using the plumbing."

"The plumbing?" John stared at Greg, "You don't think... The Chamber of Secrets--what if the entrance is in Moaning Myrtle's bathroom!"

Greg's jaw dropped open, "That... Actually makes sense!"

The boys had just reached the Staff Room when McGonagll's voice sounded, magically magnified:

" _All students to return to their house dormitories at once. All teachers return to the Staff Room. Immediately, please._ "

John turned to Greg, "It can't be another attack."

"What else could it be? And what do we do?"

John glanced around the room, eyes landing on an ugly wardrobe filled with the teachers' cloaks.

"In there, I want to hear what's going on. Then we can tell them what we know."

It was probably the worst day in John's life. He and Greg were sitting together in a corner of their common room, unable to say anything to each other. Worse was knowing that Mycroft wouldn't know until it was too late. His brother was going to die in the Chamber, and John felt sick with helplessness. 

When he saw Greg was crying silently beside him, John stood up. He wasn't about to let it end like this. 

"Come on, Greg. I'm not going to just sit here while Mycroft's brother is dying somewhere in the castle."

"Yeah?" Greg rubbed his face on the sleeve of his robes and John pretended not to notice how red his eyes were. "What do you suggest we do instead? Study?"

"We're getting my cloak, and we're going to go tell Lockhart how to get to the Chamber of Secrets."

A great deal of swearing later, John and Greg were pushing Lockhart down the large pipe in Moaning Myrtle's bathroom, and following him down into the Chamber.

"Remember," John said quietly as they headed into a dark tunnel. "Any sign of movement, close your eyes straight away."

They walked by wand light, in silence but for the occasional crunch of small animal bones shattering beneath their feet, and John tried not to imagine what Sherlock might look like when they found him.

Lockhart collapsed when John shined his wand over an enormous, twenty foot long, snake skin.

"Oh, get up!" Greg poked Lockhart with his wand.

Lockhart dived at Greg, tackling him to the ground and stealing his wand. Greg lay wide eyed on the ground as Lockhart spun to point Greg's wand at John.

"The adventure ends here, boys! I shall take a bit of this skin back up to the school, tell them I was too late to save the boy, and that you two _tragically_ lost your minds at the sight of his mangled body. Say goodbye to your memories!"

John threw himself backwards, arms over his head, as Lockhart's spell exploded Greg's Spellotaped wand with the force of a small bomb. Huge chunks of ceiling fell between him, walling him off from Greg and Lockhart.

"Greg!" John shouted. "Are you alright? Greg!"

"I'm here!" Greg's voice was muffled by the fallen rocks. "I'm okay. This git's not though--he got blasted by my wand."

"What do we do now? The whole tunnel could cave in if we're not careful!" John shouted back, knowing that if they didn't hurry, they might not make it in time to save Sherlock.

"There's no time! You go on, I'll try and shift some of the rocks... For... For when you come back..." Greg seemed to be struggling to keep his voice steady. "John?"

"Right. See you in a bit, then."

At the end of the tunnel, two entwined serpents were carved into the wall, emerald eyes glinting in the light of John's wand. He swallowed, set his shoulders back, and hissed:

" _Open_."

The chamber beyond was dimly lit, and towering stone pillars rose to support the unseen ceiling, casting dark shadows in the odd, greenish gloom.

Drawing level with the last set of pillars, John looked up to see an ancient face carved from stone, high above the sweeping stone robes. Between the statues stone feet lay a small black-robed figure, with distinctive curly black hair that could only belong to one person.

"Sherlock!" John ran to him, dropping to his knees. "Sherlock! Don't be dead! Please, don't be dead!"

John dropped his wand, pulling Sherlock's limp body into his arms. He was white as marble and just as cold, so he wasn't petrified, and John could feel the faintest bit of pulse...

"Wake up, come on Sherlock, please," John whispered, shaking him softly.

"He won't wake."

John jumped, spinning around on his knees and clutching Sherlock closer.

"Tom-- _Tom Riddle_?"

Riddle nodded.

"What d'you mean, he won't wake? He's not dead..."

"Not quite."

John stared at Riddle, who didn't look a day older than when John had seen him in the diary.

"Are you a ghost?"

"A memory, preserved in a diary for fifty years."

He pointed, and there, near the statue's giant toes, lay the little black diary John had discovered in Moaning Myrtle's bathroom, and something niggled in the back of his mind--but he had more pressing matters.

"You've got to help me, Tom," John's attention went back to Sherlock. "We've got to get him out of here, there's a basilisk, and I don't know where it is--please, help me!"

Riddle didn't move, and John was beginning to feel exasperated. He went to grab his wand, but it was not where he'd dropped it.

"Have you seen--"

It was there, twirling between Riddle's fingers. John held out a cautious hand.

"Thanks."

Riddle smiled, but didn't return the wand. Something Mycroft had said when he'd come out of the diary all those weeks ago came back to him then, ' _I believe Riddle was more involved than he let on_.'

John lowered Sherlock gently to the ground and got to his feet.

"Give me back my wand, Tom."

Riddle's smile broadened, "You won't be needing it."

John's eyebrows shot up, "What do you--there's a _basilisk_ somewhere nearby, _of course I'll be needing it_!"

"I've waited a long time for this, John Watson. For the chance to see you. To speak to you."

"We are in the _Chamber of Secrets_!" John exclaimed, losing his patience. "We can talk, all you want, later. When there's less threat of being killed by a bloody snake!"

"It won't come unless it's called. And we _are_ going to talk, now."

John glared at him, crossing his arms over his chest.

"Fine. Talk. How did Sherlock get like this?"

"An interesting question," Riddle said pleasantly. "And quite a long story. I suppose the real reason Sherlock Holmes is like this is because he opened his heart and spilled all of his secrets to an invisible stranger."

"Explain," John demanded.

"The diary-- _my_ diary," said Riddle. "Little Sherlock's been writing in it for months and months, telling me all his pitiful woes and worries: how he misses his dog something fearful, and oh, how Gregory Lestrade is so _nice_ to him--and especially how his brother has been ignoring him for _his_ friends, and how famous little John Watson stole them both away for Christmas."

Riddle's dark eyes never left his face as he spoke, a hungry look in his gaze.

"It's very _boring_ , listening to the silly little troubles of an eleven year old boy, but I was patient. I wrote back, I was sympathetic, I was kind. Sherlock simply _loved_ me. I've always been able to charm the people I needed, and Sherlock poured out his soul to me--which was exactly what I needed. I grew stronger on his fears and secrets, and soon, I was able to feed him some of my own secrets."

"Meaning?"

"Haven't you guessed yet, John?" Said Riddle softly, "It was Sherlock Holmes who opened the Chamber of Secrets. He was the one who left the messages on the wall, who let Slytherin's monster on all the Mudbloods and Filch's cat."

John stared, incredulous. _Sherlock_ had been opening the Chamber--had Mycroft figured that out too? Or would he be just as surprised as John...

"He realized what was happening of course, for all his silly worries, he's terribly clever. And who should stumble upon my diary after he threw it away but little John Watson--Sherlock had told me enough about you to make me _very_ interested, and I have _so_ many questions to ask you."

"You're interested--what questions could you want to ask _me_?" John asked.

"Shall I give you examples?" Riddle was still smiling, but his eyes were hard.

"That would nice, yes." 

"How is it that a baby, without any particular magical talent, managed to defeat the greatest sorcerer of all time? How did you survive, with nothing but an ugly scar, when Voldemort was destroyed?"

"I--why do even care? Voldemort was after your time," John said slowly, he was equally curious and worried where this was leading.

"Voldemort," said Riddle softly. "Is my past, my present, and my future, John Watson."

With a wave of John's wand, Riddle's name was written in the air:

TOM MARVOLO RIDDLE

Another wave sent the letters scrambling, forming new words from the old:

I AM LORD VOLDEMORT

John's stomach dropped.

"You see? I couldn't carry my _Muggle_ father's name, not after he abandoned me before my birth, not when I have the blood of Salazar Slytherin running through my veins. I forged myself a new name, a name people would one day fear to speak, worthy of the greatest sorcerer the world has ever known!"

John spoke in a low voice, filled with hate, "You failed."

"Have I?" Riddle said dryly.

"You're not the greatest sorcerer in the world," said John breathlessly. "So sorry to disappoint you, but the greatest sorcerer in the world is Albus Dumbledore. Everyone knows it, even when you had power you never dared attack Hogwarts. Dumbledore probably saw straight through you when were at school here, and I bet he still scares you now, wherever you're hiding."

Riddle's face transformed, the smile sliding off for an ugly look full of rage.

"Dumbledore is _gone_ , driven from the castle by the mere _memory_ of me!"

"He'll never be truly gone from Hogwarts, not so long as someone still has need of him!"

Music sounded through the Chamber as John's words echoed; a strange melody that sent chills up his spine. A large, scarlet bird burst from flames that appeared before one of the pillars, it's long tail glittering like gold as it flew towards John, dropping a scrunched up ball of fabric at his feet before alighting on John's shoulder.

"A Phoenix," said Riddle, eyeing the bird. 

"Fawkes?" Murmured John, stroking his new feathers.

"And the Sorting Hat?"

John bent down, scooping up what was indeed the Sorting Hat curiously.

Riddle burst out laughing, "Is _this_ what Dumbledore sends to defend you? A songbird and an old hat? Are you still feeling brave now, John Watson?"

John didn't know what to say--grateful though he was for Fawkes' presence, he didn't see how Fawkes and the Sorting Hat would be helpful here. At least he didn't feel so alone, and there _was_ courage to be found in that.

"Back to business, John Watson. We have met twice now, in your past and my future. Twice where I failed to kill you, and now I want to know _how_. _How_ did you survive, when countless others died at my hands?" He smiled menacingly, "The longer you talk, the longer you live."

John tried to think quickly, Riddle has his wand. John had... A songbird and an old hat. If he talked enough, he could stall, come up with a plan, but if he took too long, Sherlock would die--if he wasn't already dead, already Riddle's form was nearly solid, not the ghostly appearance of earlier.

"No one's really sure what happened that night," said John abruptly. "But I know I survived because of my mum--my _Muggleborn_ mum. She died to protect me, she loved me _so much_ that she gave up her life for mine. And that destroyed you--I know, I saw what you became last year. You're nothing but a parasite, forced to live off others to survive, forced to hide your great ugly face--you repulsive monster!"

Riddle sneered before his lips curled into a horrible smile.

"So. Your mother died to save you--a powerful bit of magic I suppose, but I can see now that _you_ are nothing extraordinary. I wondered, you know... There's such a strange resemblance between us, John Watson. Even you must have noticed, though, in the end, you've only survived this far out of luck. And that's all I wanted to know."

John didn't have time to panic.

" _Speak to me, Salazar, greatest of the Founding Four!_ "

There wasn't much John could do, one look in the basilisk's eyes and he was dead. He ran blindly, hands against the walls to guide him--useless as he stumbled and fell. He could hear Riddle laughing, and then screeching:

" _Not the bird! Leave the bird and kill the boy! Smell him! Kill him!_ "

John risked a glance; Fawkes had blinded the basilisk. He'd be more relieved if he had any way of defending himself, the snake's sense of smell had not been harmed. He ducked down as the tail end whipped towards him, and was hit in the face by the Sorting Hat.

He wasn't sure why he did it, in hindsight it was an absurd thing to do when facing down the King of the Serpents. But now John had sword, and he wasn't about to argue.

The basilisk lunged at John, and he dodged out of the way, swinging the sword as he went, again and again. Riddle was screaming at the snake, but John couldn't hear the desperation in it--he couldn't hear it at all. The basilisk came at John again, and this time John stood his ground, stabbing upward with all his strength.

His shoulder was burning, a fang had embedded itself there and he pulled it out as he fell to his knees. His vision blurred, the Chamber was spinning--something red rubbed it's head against John's arm with a sad trill.

"Fawkes," John said weakly. "You were amazing."

The Phoenix rested his head against John's slumped shoulder.

"You're dead, John Watson," Riddle's voice sounded just above his head. "Dead. Even Dumbledore's bird knows it. Do you know what it's doing, Watson? It's crying."

He was right. John blinked. Great pearly tears dripped down Fawkes's face.

"I think I'll wait here and watch you die, John Watson."

John didn't care, he was too tired. Too dizzy.

"Here ends the famous John Watson. Alone in the Chamber of Secrets, you'll be with your Mudblood mother soon..."

Was this what dying felt like? John imagined everything would fade away, and here everything was, getting clearer by the moment. He could see Fawkes, and the tears that coalesced around the wound on his shoulder, a wound that was no longer there.

 _Phoenix tears_ , of course. Mycroft was going to smack him later.

"No! Get away bird! Go away!"

Riddle pointed his wand at John, eyes dark and wild.

"I'll just have to finish you myself--"

Fawkes dropped a small black book--the diary--in John's lap. For a moment, both he and Riddle stared at the diary, before John tightened his grip on the fang he'd pulled from his shoulder and slammed it into the diary--a loud scream pierced the air as Riddle contorted, and then, he was gone.

John stayed on his knees, trembling in the aftershock. 

"Greg'ry?"

John jumped to his feet, Sherlock had awoken.

"Oh..." Sherlock groaned as he sat up. "John..."

John helped him stand, keeping an arm around Sherlock even as he protested feebly.

"Greg's here too, there was... An accident, he's waiting for us at the cave-in, hopefully he's cleared enough space for us to get through..."

Greg had cleared a small path, enough for John and Sherlock to pass through. Sherlock attached himself to Greg without so much as a glance at the gibbering Lockhart behind him.

"I'm sorry, Greg, I tried to tell you, I did, I just... It was me, and I didn't mean for it to go this far, I didn't know... I--"

"Hey, what's this, then?" Greg patted Sherlock's back, giving John an odd look over his head.

Sherlock muttered something into Greg's robes.

"What was that?"

"Is Mycroft going to hate me?"

Greg hugged Sherlock close, "Mycroft could never hate you, your his brother, no matter what."

"But I petrified him!"

"That's what brothers do, he'll get used to it."

"Not because I'm dying to interrupt or anything, but maybe we could worry about Mycroft when we get _out_?" John cut in.

"Is that Professor Longhorn?" Sherlock asked suddenly.

"Prof---who?"

"Professor Longhorn, our Defense idiot, the dunderhead Mycroft's moronically infatuated with."

They were a bit later than expected leaving the Chamber, John and Greg were still giggling as they hung onto Fawkes. Sherlock was never sure what they found so amusing.

As they took turns explaining what had happened, Sherlock let everyone know how low wizarding standards must be if he'd had to be saved by the likes of Gregory Lestrade and John Watson--mentioning Mycroft's part in it all pacified him very slightly.

For John's part, he was impressed to learn that the sword he'd freed from the hat had belonged to Godric Gryffindor--Dumbledore said that only a true Gryffindor could have pulled the sword out, and John wasn't sure what he thought of that, sitting beside Greg and Mycroft--and Sherlock--at the impromptu feast. 

Was it so bad, being a bit Slytherin? After all, he had almost been one. He glanced over at the Slytherin table, wondering how much would have changed. John was pulled from his thoughts by a hand on his shoulder.

" _Everything_ would have been different, but for argument's sake, I think were both better off where we are," said Mycroft quietly.

They watched Moriarty muttering darkly with several older Slytherins before John nodded, "Yeah, I reckon you're right..."

"What're you two whispering about? This is supposed to be a party!" Greg said loudly around a mouthful of pie. "John! Sherlock says muggles use fellytones for talking--barking mad, but we should try it this summer!"

Mycroft put his face in one hand, ("Of all the _hair-brained_ ideas,") as John piled dessert onto his plate and explained telephone numbers.

This summer was bound to be better than the last.

**Author's Note:**

> On to Year 3! 
> 
> If anyone's got any suggestions for anything, I'm very willing to hear them--especially regarding any character swaps. I've got ideas for some of the as-of-yet unseen Sherlock Holmes characters (I'm particularly excited to introduce Sebastian Moran later).


End file.
